Paris Despatch | International

The Indian hand in a French satellite

Vincent Lapeyrere’s day at work starts with a 200 m walk from his office to the ground station at the Meudon Observatory outside Paris. He has a 10-minute window to issue commands to the PicSat satellite as it flies over Paris, which it does four times a day. Mr. Lapeyrere and his team are trying to reduce PicSat’s spin by providing torque through on-board magnetorquers. Picsat is expected to become stable in two weeks, after which it will commence its mission of studying the star Beta Pictoris and try to detect the transit of its exoplanet Beta Pictoris b.

It took the PicSat team just three years to design and build the nano satellite, which is made of three cubes, each just 10 cm in length, weighs no more than 3.5 kg and is equipped with a telescope which is 5 cm in diameter. The Indian Space Research Organisation (ISRO) played a pivotal role in the project’s quick execution as its PSLV launcher successfully placed the satellite in the helio-synchronous orbit (about 500 km in altitude), on January 12.

Sylvestre Lacour, who is the principal investigator of the PicSat project, said they chose ISRO as they wanted the satellite in the orbit at the earliest. “ISRO has been very successful in deploying cubesats. Their schedule is fast and flexible, making it possible to get a slot at a short notice. And equally important, it is inexpensive,” he said. Besides PicSat, PSLV’s 42nd flight deployed 30 other satellites in space. Last February, ISRO managed to deploy a staggering 104 satellites in a single flight. They followed it up with a successful launch of 31 satellites in June. PicSat’s mission is expected to last for a year, during which time it will be continuously monitoring Beta Pictoris, which is located about 63 light years from the Earth.

Transit phenomenon

Mr. Lapeyrere listed multiple reasons why this star was chosen. “It’s a very young star, only 20 million years old. There is a debris disk around the star where the planet Beta Pictoris b was discovered a few years ago. It’s a very young planet and is still in its formation phase. Studying this planet could improve our understanding of how planetary systems are formed,” he said. PicSat will gather information about the planet by observing the transit phenomenon, when the planet passes in front of the star resulting in the change of its luminosity. By using this method, researchers can derive information about the size, density and composition of the planet. However, the transit window is quite small.

According to Mr. Lacour, it could happen any time. “The transit phenomenon occurs every 18 years. And viewing from earth, this phenomenon lasts for a few hours. We don’t know the exact timing of this transit. It is for this reason that the star system has to be monitored continuously from space,” Mr. Lacour said. Since PicSat flies over Paris for just half an hour every day, radio amateurs the world over have been encouraged to collaborate in the project. “Amateur astronomers with a radio antennae can receive the satellite data and relay it to the PicSat database. The more data we collect, the better,” system engineer Lester David explained.

In order to stabilise the satellite, an electrical current is run through the copper coils using on-board batteries and a solar array. “The current creates a magnetic field around PicSat which is already inside Earth’s magnetosphere. The magnetic field created by the coils align with Earth’s magnetic field. That’s how we are keeping PicSat stable,” said Mr. David, who was at Sriharikota to witness the January 12 launch.

Dhananjay Khadilkar is a freelance journalist based in Paris

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Printable version | Feb 21, 2020 8:38:58 PM | https://www.thehindu.com/news/international/the-indian-hand-in-a-french-satellite/article22716332.ece

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